The present invention relates to a punch press device for stamping out core plates for motor cores from a hoop material, which is used in manufacturing motor cores such as stator cores or rotor cores.
Specifically, Japanese Examined Patent Publication No. 2-36332 discloses a method for manufacturing motor cores M such as rotor cores. According to the disclosure of this document, as shown in FIGS. 5 and 6, a punch press device stamps out core plates P consecutively from a metal hoop material and laminates a plurality of stamped out core plates P. Protrusions Pa are formed on each core plate F. The protrusions Pa of a core plate P are engaged with recesses on the back face of the adjacent core plate P. Thus, the plurality of core plates P are joined to each other in a laminated state. Also, for example, on every 100th core plates P to be laminated, holes Pb are formed instead of protrusions Pa. When the protrusions Pa of a core plate P are engaged with the holes Pb of the adjacent core plate P, the core plate P having the holes Pb does not engage with the adjacent core plate P. Thus, the laminated core plates P are separated at every nth piece. The motor core M is composed of groups of a predetermined number of laminated core plates P.
As described above, in the case where a plurality of core plates P are stamped out by a punch press device, holes Pb are punched out, instead of formation of protrusions Pa, on every nth core plate, where n is a predetermined number. In this case, as shown in FIG. 7, holes Pb are preformed at the points on the hoop material W from which core plates P will be punched out. No hole Pb is formed at the points on the hoop material W where core plates P having protrusions Pa will be stamped out. After that, when protrusions Pa are formed at the points on the hoop material W from which core plates P will be stamped out, the portions having the holes Pb on the hoop material W are blank-stamped by the punch press device. Therefore, no protrusion Pa is formed on the portions where the holes Pb have been formed on the hoop material W.
As a punch press device as described above, proposed are, for example, the punch press devices having the configurations as shown in FIGS. 8 to 11.
As shown in FIG. 8, when the switching member 45 is moved to the right end in FIG. 8 by the shift plate 46, the upper end face of the punch 44 is brought into contact with the lower face of the switching member 45. As a result, the punch 44 is constrained so that it cannot be moved upward relative to the lift 43. Therefore, when the lift 43 moves down toward the hoop material W, the punch 44 moves down together with the lift 43. Thus, holes Pb are formed on the hoop material W by the punch 44.
On the contrary, when the switching member 45 is moved to the left end in FIG. 8 by the shift plate 46, the upper end 44a of the punch 44 is disposed in the recess 45a of the switching member 45. As a result, the punch 44 is released from the constrained state as described above and is allowed to move up relative to the lift 43. Therefore, when the lift 43 moves down toward the hoop material W, the punch 44 is brought into contact with the hoop material W as shown by the chain lines in FIG. 8, thereby moving up relative to the lift 43. As a result, no hole Pb is formed on the hoop material W by the punch 44.
According to the configuration shown in FIG. 8, the switching member 45 reciprocates between the constraining position and the releasing position. To that end, an air cylinder 47 is supported by the side of the lift 43. The air cylinder 47 is connected to the shift plate 46 via the piston rod 47a. The piston rod 47a of the air cylinder 47 projects and retracts, thereby changing over the position of the switching member 45 between the constraining position and the releasing position. Thus, holes Pb are punched through the hoop material W.
According to the configuration shown in FIG. 9, a servo motor 48 is supported by the side of the lift 43. A cam 49 is installed to the motor shaft 48a of the servo motor 48. A contact roller 50 that can come in contact with the cam 49 is supported on one end of the shift plate 46. On the other end of the shift plate 46, a spring 51 is attached, which biases the contact roller 50 toward a direction where it is brought into contact with the cam 49. The cam 49 is rotated by the servo motor 48, thereby changing over the position of the switching member 45 between two positions, the constraining position and the releasing position.
According to the configuration shown in FIG. 10, a servo motor 48 is supported by the punch press device body 52. A cam 49 is provided for the motor shaft 48a of the servo motor 48. An interlocking member 53, while being inserted into through hole of the body 52, is supported so that it can move in the same direction as that of the switching member 45. A contact roller 50 that can come in contact with the cam 49 is supported on one end of the interlocking member 53. On the other end of the interlocking member 53, a sliding contact plate 54 is installed. A contact portion 55, which can slidably contact with the sliding contact plate 54, is installed on one end of the shift plate 46. A spring 51 is installed on the other end of the shift plate 46. The cam 49 is rotated by the servo motor 48, thereby allowing the switching member 45 to move via the interlocking member 53. Thus, the position of the switching member 45 is changed over between two positions, the constraining position and the releasing position.
According to the configuration shown in FIG. 11, an electromagnetic solenoid 56 is supported by the side of the lift 43. The movable iron core 56a of the electromagnetic solenoid 56 is connected to one end of the shift plate 46 via the connecting plate 57. On the other end of the shift plate 46, a spring 58 is installed, which biases the switching member 45 toward the left direction in FIG. 11. When the electromagnetic solenoid 56 is demagnetized, the switching member 45 is switched to the releasing position by the biasing force of the spring 58. Therefore, no hole Pb is formed on the hoop material W. When the electromagnetic solenoid 56 is excited, the position of the switching member 45 is changed over to the constraining position against the biasing force of the spring 58. As a result, holes Pb are formed on the hoop material W.
The above conventional configurations, however, have the problems described below.
In the conventional configuration shown in FIG. 8, an air cylinder 47 is used as a driving source for changing over the position of the switching member 45 between the constraining position and the releasing position. In this case, there is a problem in that the responsiveness of the air cylinder 47 is not good, resulting in reduction of the tracking performance in punching of holes Pb at high speed.
In the conventional configuration shown in FIG. 9, a servo motor 48 is used as a driving source for changing over the position of the switching member 45. There is a problem that the servo motor 48 moves up together with the lift 43 and vibrations caused by the elevation of the lift 43 are transmitted to the servo motor 48, resulting in frequent occurrence of failure in the servo motor 48.
In the conventional configuration shown in FIG. 10, a servo motor 48 for changing over the position of the switching member 45 is supported by the punch press device body 52. This prevents vibrations caused by the elevation of the lift 43 from being transmitted to the servo motor 48. It is necessary, however, to place an interlocking mechanism such as the interlocking member 53 between the cam 49 rotated by the servo motor 48 and the shift plate 46 supporting the switching member 45. This results in a problem in that the structure of the device becomes complex.
In the conventional configuration shown in FIG. 11, the position of the switching member 45 is changed over to the releasing position by the biasing force of the spring 58, and the position of the switching member 45 is changed over to the constraining position by excitation of the electromagnetic solenoid 56. Therefore, there is a problem in that the position of the switching member 45 cannot be changed over when the spring force of the spring 58 is reduced due to continued use of the device.